Zinnia in Zone 9a & 9b
Zinnia elegans
Yes, zinnia grows in zones 9a and 9b. Start seeds indoors Jan 18–Jan 25 and plant out Feb 22–Mar 1.
When to plant zinnia in zone 9b
Zones 9a and 9b share the same average frost dates, so this page covers both.
Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Either works.
| Start indoors | Jan 18–Jan 25 |
|---|---|
| Direct sow / transplant outside | Feb 22–Mar 1 |
| Estimated bloom | Apr 28–May 5 (~65 days after planting) |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-4 ft.
Plant alongside it in zone 9b
These go outside within two weeks of zinnia in zone 9b, so one planting day can cover them.
- NasturtiumFeb 22–Mar 1
- MarigoldFeb 22–Mar 1
- Ageratum (Flossflower)Feb 22–Mar 1
- AmaryllisFeb 22–Mar 1
- Annual Geranium (Pelargonium)Feb 22–Mar 1
- Butterfly Weed (Asclepias)Feb 22–Mar 1
Zinnias are about as forgiving as annual flowers get: direct-sow them after frost, give them sun, and they bloom fast and heavily with almost no fuss, throwing up daisy or dahlia-form flowers in almost every color except true blue on plants anywhere from 1 to 4 feet tall. They've also earned their spot in a vegetable garden on merit. They're one of the better-documented pollinator draws for nearby crops, beyond their good looks as a border filler.
How zinnia fits zone 9's season
Zone 9b's frost-free window runs about 293 days, from February 15 to December 5. Zinnia needs about 65 days from sowing to first bloom.
Zinnia planting windows in every zone
Zone 9b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Bloom |
|---|---|---|---|
| 2a & 2b | Apr 22–Apr 29 | May 27–Jun 3 | Jul 31–Aug 7 |
| 3a & 3b | May 2–May 9 | Jun 6–Jun 13 | Aug 10–Aug 17 |
| 4a & 4b | Apr 17–Apr 24 | May 22–May 29 | Jul 26–Aug 2 |
| 5a & 5b | Apr 12–Apr 19 | May 17–May 24 | Jul 21–Jul 28 |
| 6a & 6b | Mar 28–Apr 4 | May 2–May 9 | Jul 6–Jul 13 |
| 7a & 7b | Mar 13–Mar 20 | Apr 17–Apr 24 | Jun 21–Jun 28 |
| 8a & 8b | Feb 25–Mar 4 | Apr 1–Apr 8 | Jun 5–Jun 12 |
| 9a & 9b (your zone) | Jan 18–Jan 25 | Feb 22–Mar 1 | Apr 28–May 5 |
| 10a & 10bSpring window | Feb–May | Mar–Jul | ~65 days after transplanting |
| 11a & 11b | Dec 4–Dec 11 | Jan 8–Jan 15 | Mar 14–Mar 21 |
Bloom dates are about 65 days after the sow or plant-out date, not after starting seeds indoors.
Zone 2 sows before zone 3 here, which looks wrong and is not. USDA zones rank winter cold, not season length, and zone 2 is mostly interior Alaska, where hard winters come with warm summers. More on what a zone measures.
Good companions
- Tomato: Attracts pollinators and hoverflies that improve fruit set and help control aphids.
- Cucumber: Attracts pollinators that improve fruit set.
Where to buy zinnia seeds
Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds (each supplier's zinnia seeds)
Varieties we recommend, and where to get them:
- 'Profusion' series: A different species cross (Zinnia marylandica), 12 inches tall and 20-24 inches wide, that University of Wisconsin-Madison Extension notes for strong heat, drought and disease tolerance. Buy: True Leaf Market Full notes
- Queeny Lime with Blush (best for cut-flower color): Johnny's grows this Queeny series pick to 30-40 inches with mostly double, 2- to 3.5-inch blooms in a lime-green-and-blush color combination unlike any of the three series above. Buy: Burpee Full notes
- Double Zahara Salmon (best for containers, powdery mildew): Johnny's Zahara series stays compact at 12-20 inches with a low, mounding habit and is specifically bred for powdery mildew resistance, the disease this profile flags as zinnia's main problem. Buy: Burpee Full notes
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing zinnia" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 9b calendar · Plan your beds in the Garden Designer →
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Growing Zinnia in USDA zone 9b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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